Wind Turbine Lightning Protection Bypassing Bearings
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Solution Overview
Problem
Wind turbine generator systems are prone to bearing damage from lightning strikes due to high impedance in the existing discharging paths, leading to increased maintenance costs and operational interruptions.
Innovation Solution
A lightning protection device that creates a separate discharging path for lightning currents, bypassing the pitch and main rotor bearings by using flexible insulated cables and slip rings to direct the current through cavities in the pitch bearing, hollow rotor shaft, and yaw bearing, ensuring safe discharge to the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the existing metal casting parts and structural parts are used as conducting paths for lightning current, then the structure is simple and cost-effective, but the impedance of the discharging path is high which damages the bearings
Solution Approach 1:
The conducting path is segmented into two separate paths: one for mechanical support (metal casting parts and structural parts) and another for lightning current discharge (dedicated conducting path with low impedance). This segmentation allows the lightning current to bypass the bearings through the dedicated path, preventing bearing damage while maintaining structural simplicity.
Solution Approach 2:
A dedicated conducting path acts as an intermediary element, providing a low-impedance route for lightning current to flow from the blade arrester directly to ground, bypassing the bearings. This intermediary path protects the bearings from lightning damage without requiring changes to the existing structural components.
2Ease of manufacture
If the lightning current flows through the pitch bearing and main rotor bearing, then the existing structure can be used, but the high impedance causes bearing burn and damage
Solution Approach 1:
The lightning current discharge function is extracted from the mechanical structural components (pitch bearing and main rotor bearing). A separate conducting path is created that extracts the lightning current flow away from the bearings, preventing the harmful thermal and electrical effects that would otherwise damage the bearing components during manufacturing and operation.
3Reliability
If separate cable wires are used inside the blades for lightning protection, then the bearing damage is prevented, but the device complexity and maintenance cost increase
Solution Approach 1:
The conducting path components are merged with the existing structural elements of the wind turbine. The path utilizes existing components such as the hub, rotor shaft, and tower structure, combining the lightning protection function with the mechanical support structure. This integration reduces device complexity and eliminates separate cable wire installations while maintaining bearing protection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents bearing damage from lightning strikes, reducing failure rates and maintenance costs by providing an efficient and insulated path for lightning current discharge, thus ensuring continuous operation of the wind turbine generator system.
Implementation Method 1
a blade arrester (6) located near the blade tip and located at the side of the blade for receiving the lightning current
Implementation Method 2
The lightning-proof element of the pitch bearing (8) is provided at the blade root, one end of the lightning-proof element of the pitch bearing (8) is connected to the down lead of blade (7) and the other end is connected to the lightning-proof element of the rotor bearing (9)
Implementation Method 3
the impedance of the path through which the lightning current passes is high, which influences the discharging of the lightning current
Data Source
AI summary
A lightning protection device for a wind turbine generator system includes at least a blade arrester, a down lead of a blade connected to the blade arrester, a lightning-proof element of a pitch bearing, a lightning-proof element of a rotor bearing. The lightning-proof element of the pitch bearing is arranged at the blade root, with one end connected to the down lead of blade and the other end connected to the lightning-proof element of the rotor bearing. The lightning protection device forms a lightning current conducting path passing through a cavity of the pitch bearing, a hollow of a rotor shaft and a cavity of the rotor bearing. A wind turbine generator system having the above mentioned lightning protection device is provided.